Machine for making plaster board



I G. A. NEW

IIACHINE FOR MAKING PL ASTER BOARD- Aug. 12, 1930.

3 She ets-Sheet 1 Filed May 24, 1929 3 Sheets-Sheet 2 /NVE/VTOR 6057A VE A- NE W ,arroie/vfirs G. A. NEW

CHINE FOR MAKING PLASTER BOARD Filed May 24. 1929' H 1 Q Q NW Aug. 12, 1930.

Aug. I2, 1930. G. NEW 7 Q CHINE FOR MAKING PLASTER BOARD Filed May 24, 1929 3 Sheets-Sheet 5 G TAV M 7- M ATTORNEI S llllllalalllllll lllll'kl'l II.

atented Aug. 12, 1930 lfA-TENT OFFICE G'UBTAVE A. NEW, OF PORT CLINTON, OHIO, ASSIGNOR TO' AMERICAN GYPSUM GOM- PANY, OF PORT CLINTON, OHIO, A CORPORATION OF OHIO MACHINE FOR MAKING PLASTER BOARD This invention relates to an improved machine for making plasterboard, and more particularly to apparatus to be used in conjunction with a plaster or wallboard machine for reinforcing the open edges of the board with a woven mesh fabric.

The process and the machine used in the manufacture of the plasterboard in so far as concerns the bringing together of the paper covering sheets and the intermediate layer of wet: plaster, the reduction of these materials to t e form of board of the desired thickness, an the several finishing operations, including the drying of the board, follows generally that now in general use in the industry, being characterized by the continuous feeding of the materials to the machine at one end and the continuous discharge of the finished product at its other end.- It will be understood, therefore, that this disclosure presents nothing new in the art of plasterboard manufacture per se, but rather in the continuous feeding, folding and introduction of the fabric reinforcing material into the edges of the board during the manufacturing process.

. The apparatus described in this application is particularly adapted to carrying out the process and manufacturing the product disclosed in my United States patent application, Serial No. 364,478 filed May 20, 1929 and in my United States patent application, Serial No. 264,658, filed March 26, 1928.

For the purpose of illustration, a portion of a typical designed continuous process machine has been shown in the accompanying drawings, with the addition of the novel mechanism for folding and feeding the edge reinforcing material. Thus:

Figure 1 is a fragmentary view in side elevation of the head end of a plasterboard machine showing the location of the tape folding devices.

Figure 2 is an enlarged perspective view at the pressure rolls showing the tape being guided into the edge of the board as it is formed.

Figure 3 is an enlarged view in vertical section taken on line 33 of Figure 2.

Figure 4 is an enlarged view in front elevation of the tape folding devices.

Figure 5 isa top plan view of the tape foldmg devices.

Figure 6 is a view in vertical section taken on line 6-6 of Fig. 5.

Figure 7 is adetail view in vertical section taken on line 77 of Figure 4.

Figure 8 is a perspective view showing the manner in which the tape is folded and creased in the first folding operation.

.Figure 9 is a view in end elevation of the T-folding device shown on the left in Figure 4.

Figure 10 is a perspective view of the hinged folder block of the T-folding'device.

Figure 11 is a perspective view of the shoe of the T-folding device.

Figures 12 to 16 are cross-sectional views 'of the tape showing the manner in which the tape is folded from U-form to its final T- form.

Figure 17 is a view showing a modified form of the T-folding device.

Figure 18 is a top plan view of a modified form of the U-folding device.

Figure 19 is a cross-section showing an alternative method of folding the tape into a T-form, only part of which is of double thickness.

The plasterboard machine, so far as it has been illustrated, comprises in general a horizontal endless belt 1, which may be several hundred feet in length and slightly wider than the width of the finished board, of say 48 inches. This belt ismounted on two mam pulleys 2, one being located just ahead of a pair of pressure or squeeze rolls 3, 3. Rearwardly of the pressure rolls is a table 4 with its surface in horizontal line with the top of the lower pressure roll. The paper 5 for the bottom sheet of the plasterboard, is fed from a roll 6 located at some convenient point rearwardly and below the table 4, the paper being advanced from the roll onto the table 4 and thence forwardly over the top thereof. Above the table is located the discharge end of a wet plaster conveyer 7 consisting of a traveling belt, preferably leading from a source of plaster supply at one side of the plasterboard machine.

At some point above and rearwardly of the the upper pressure roll, and thence forwardly,

as the top sheet of the board.

As the wet plaster is discharged onto the advancing bottom sheet 5 from the conveyor 7, it is spread laterally to cover the surface so that as the squeeze rolls are reached, there is a simultaneous reduction of the plaster to a uniform thickness and the application of the top sheet, it being observed that the upper squeeze roll is spaced above the belt a distance to give the desired thickness which for the purpose of this disclosure may be assumed to be three-eighths of an inch.

To confine the wet plaster between the two covering sheets and to provide s uare edge faces along the side edges of the oard, the

machine is equipped with edge forming members termed side dams 9, 9. one being located on each side of the machine and extending rcarwardly from the ends of the upper squeeze roll 3. In their simplest form, these side dams are plates of wood or metal supported on edge just above the table 4 with their inner faces in line with the edges of the board. The forward ends of these side dams are curved to conform to the surface of the top roll 3, and to form narrow points 9 which project into the space between the rolls, as shown in Figure 2. In addition to the side dams 9, 9, there are feed plates for guiding the edge reinforcing material into the board as it passes through the pressure rolls. These plates will be discussed at a later point in the disclosure.

From the pressure rolls the materials assembled in the form of the finished product are carried along on the main belt 1 for a. considerable distance giving the wet plaster an opportunity to set before it is cut into lengths and dried. During the advance movement of the board it may be subjected to further surface and edge smoothing treatment as may be necessary to produce a uniform and commercially satisfactory product.

The process thus far disclosed may be considered as typical for the manufacture of what is generally known as a raw or open edged plasterboard, that is, a board in which the edges ofothe top and bottom covering sheets terminate flush with the edges of the board leaving the full thickness of the plaster body exposed along both side edges, as distinguished from the so-called covered or bound edged types of plaster or wall board. in which the margins of one or both covering sheets are folded over or into the side edges in such a manner as to partially or entirely enclose the plaster body with paper.

Referring now to the process and instrumentalities for reinforcing the edge With a woven fabric, the same contemplates the use of a relatively inexpensive woven muslin-like fabric which has been treated with a glue or sizin to ive it a certain de ree of stiffness.

D b b folded and creased to the desired cross-sectional contour and then guided between the edges of the covering sheets just before or as they pass through the squeeze rolls, the strips having been folded so that one portion will reinforce the edge faces of the plaster body between the margins of the covering sheets and another portion will be embedded edgewise in the plaster body to provide an anchorage therein.

In general, the fabric is ,folded from its initial form as a flat strip to that of a T, the portion corresponding to the cross bar of the T vultimately reinforcing the edge of the plaster body and the portion corresponding to the upright of the T being embedded in the plaster body substantially midway of its thickness. The flat strip may be first folded double along a median line and the two marginal portions when folded outward in opposite directions to form the T, as illustrated in the drawings in Fig. 19 or the strip may befirst folded into U-form, as shown in Fig. 12, and then the two edge portions brought together in substantially the steps shown in Figs. 13, 14, and 15 and folded over upon the base portion, as shown in Fig. 16. While either method of folding the fabric is satisfactory, the latter is preferable, as it provides a double thickness of fabric to strengthen the plaster edge. Moreover, the second form lends itself to a complete folding of the material into its ultimate form before it is fed into the edge of the board,

due to double thickness throughout, whereas with the first form (Fig. 19) the folded margin would be led into the plaster body with the free marginal portions projecting beyond the edge faces to be then spread apart and folded down against the said edge face.

The mechanism for folding the fabric into the form shown in Fig. 16 and feeding it into the edge of the plasterboard during the course of manufacture will now be described.

Along opposite sides of the machine and extending rearwardly from the table 4 are two horizontal supporting plates 10 mounted just above the level of the top of the table. Each plate is of suflicient length to support the several fabric folding devices in spaced relation and generally in line with the edges of the finished product. Since the fabric folding equipment is the same on opposite way between its top and sides of the machine, only one set of folding devices will be described, it being understood that both edges of the board may be treated in the same manner.

At the extreme rear end of the plate 10 is mounted a suitable spindle 11 onto which are placed the rolls 12 of the narrow fabric or tape, the spindle being upright so that the tape is fed forwardly from the roll in a vertical flat strip or web, which for convenience will be designated as A.

Forwardly of the spindle 11, is an upright face plate 13 bolted to the supporting plate 10, with its outer face flush with the outer edge thereof. Mounted on the outer face of this plate are a series of guiding, folding and creasing members which receive the tape in its flat form A and fold and crease it to its initial form shown in Fig. 12. These devices will now be described in order, from right to left, (Figures 4 to 7). At the extreme right end of the plate is a tape guide consisting of an upright metal strip 14 adjustably mounted on the face of the plate 13 and having a shorter stri 15 hinged to the strip 14 near its lower en and held againstthe same at its free edge by a spring clip 15. The hinged strip forms a narrow vertical slot through which the tape A is threaded and by adjusting the guide vertically, the center line of the tape can be made to coincide with the center line of the folding devices therebeyond so that the uniformity of the folds may be preserved.

Beyond the tape guide 14 is a mandrel 16 consisting of a thin metal block fastened edgewise to the plate 13 a proximately midhottom edges, and extending longitudinally from the center toward the front edge. the mandrel is tapered to an inclined edge facing rearwardly and terminating just short of the tape guide 14. Just above and below the rear or oint end of the mandrel is mounted a pair of spring fingers 17, 17 extending parallel with the mandrel and secured to the plate at their end edges adjacent the tape guide 14. The fingers 17, 17 are bent transversely to provide free end portions which stand away from the face of the plate, the distance being regulated by thumb screws 18, 18 passing through the plate 13 and bearing against the backs of the spring fingers. Just beyond the spring fingers 17, 17 is a metal strip 19 arranged vertically and transversely of the plate 13, and hinged at its lower edge, its upper edge being detachably held against the plate 13 by a spring .catch 19*. The central portion of this strip is bent outwardly in U-shape as at 19 and straddles the mandrel 16 just short of the point where the inclined edge portion of the mandrel joins its straight edge portion, which continues on to its opposite end.

The forward end of Near the forward end of the plate- 13 is a set of three creasing rollers, two of the rollers 20, 20 being journalled above and below the mandrel and having rolling contact with the top and bottom surfaces thereof, while the t ird roller 21 rotates on a vertical axis and is adapted to bear against the outer edge of the mandrel 16.

These rollers are mounted so that they can be shifted bodily away from the man drel to permit.the threading of the strip between the rollers and the mandrel and it is for the same reason that the tape guides, heretofore described, have hinged parts which can be swung outwardly or opened to allow for the threading of the strip.

The mounting of the top and bottom rollers 20, v20 will be described first: The rollers are journalled on hearing pins 22, 22 which extend through curved slots 23, 23 formed in r the top and bottom edges of the plate 13 (Figure 6) and are anchored in the ends of two lever arms 24, 24 on the back face of the plate and extending lengthwise thereof,

ing flatwise against the face of the plate 13.

Anchored in the plate 13 are dowel pins 28, 28

which pass through holes in the plate 27 and between the dowel holes is anchored a bolt 29 extending through the plate 13 and some distance beyond the rear face thereof.

A coil spring 30 surrounds the shank of the bolt and bears at its ends against the back of the plate and the head of the bolt. By virtue of this mounting for the edge roller 21, it follows that if the bolt 29 is forced endwise against the spring 30, the bearing bracket 27 will carry the roller away from the edge of the mandrel. I

In order that all of the rollers 20, 20 and 21 may be shifted simultaneously and by the manipulation of the same means, the following construction is used: Pivotallv mounted to the back of the plate 13 and between the forward or free ends of the lever arms 24. 24

is a square cam 31 having a long lever arm or handle 32 projecting upwardly and rearwardly away from the front end of the plate 13, (Figure 6). The cam is so shaped that by pressing down on the handle the lever arms 24, 24 will be spread apart thus shifting the rollers 20, 20 bodily in opposite directions, with their journal pins 22 moving in the slots 23. Integral with the handle 32 nea r its lower end is a thin blade-like cam 33 extending downwardly and outwardly, with its end portion in bearing contact with the head of the bolt 29, anchored in the bracket 27 of the edge roller 21. As the lever handle 32 is pressed down the cam 33, owing to its inclination to the vertical, as shown in Fig ure 7, acts toforce the bolt endwise and forwardly thus shifting the plate 27 on its dow els away from the plate 13, with the result that the edge roller 21 is shifted from the mandrel simultaneously and in the same amount as are the top and bottom rollers 20, 20.

Considering now the passage of the tape through the folding and creasing members on the plate 13, it is clear from Figure 4 that the fabric leaves the right-hand guide as a flat upright strip A. As it reaches the inclined ends-ref the mandrel it gradually assumes a U-shape, first quite flat with its edges still lying in their original plane as they pass over the spring fingers 17, 17. On reaching the guide strip 19 the edge portions have been brought closer together and more nearly horizontal, whereupon the strip is carried into the straight portion of the mandrel which defines its U contour. On passing through the rollers 20 and 21 the strip is given its preliminary square U-shape by the creasing action of the rollers along the lines of the right angled folds, as shown at A in Figure 8.

As an alternative and somewhat simpler means for creasing the tape on the mandrel, a pair of flat leaf springs 34, 34 may be secured at the top and bottom edges of the plate 13 with their free ends bearing against the mandrel as shown in Figure 17.

From the creasing rolls the U-shaped strip passes over the forward edges of the mandrel and thence to a final folding device which converts the tape from a U-shape to a T-shape, it being observed from Figure 5 that the folder now to be described is set inwardly a short distance from the line which the tape has heretofore been following, so that as the tape leaves the mandrel it changes direction slightly with the accompanying effect of drawing the creased tape over the corners of the mandrel thus tending to make the creases sharper and more permanent.

The T-folder or crimper, as it may be called, will now be described (Figures 4, 5,

9, 10 and 11) Elevated slightly aboveithe' supporting plate 10 is a two-part folding block 35, consisting of two hinged sections or halves, one above the other, the lower section being bolted to a plate 36 (Figure 9) extending beyond the front and rear edges of the hinged folder block 35 and bolted in turn to the main supporting plate 10.. The two sections of the block 35 are connected by a hinged plate 35 extending along their rear faces. Along the front face of the folder block 35 is a T-shaped slot 37 made up of a comparatively wide shallow recess 37 a in the faces of the two sections and a deep narrow slot 37* extending inwardly from the shallow recess. This recess and slot are formed in the opposing faces and outer edges of the two hinged sections so that when the same are closed, a continuous slot of T-section extends from end to end. The ends of the slots are preferably flared as shown in Figure 10, to eliminate sharp edges at the points where the'tape enters and leaves the folder block. Fastened to the top surface of the upper section of the folder is a plate 38 projecting forwardly Well beyond the front edge of the block and having a flange 38 at its forward edge which bears against the bottom plate 36. A spring clip .39 is secured at the bottom edge of the bottom plate and is provided with a detent at its upper end which engages the corner edge of the upper plate to normally hold the hinged parts together.

Within the space between the front edge of the folder block and projecting ends of the plates 36 and 38, is a shoe 40 (Figure 11) consisting of a metal block adapted to bear edgewise against the front face of the folder block 35. Anchored in the outer face of the shoe is a pair of rods, 41, 41 passing through bushings or sleeves 42, 42 mounted in the flange 38 of the top plate 38, said bushings having threaded connection so that they may be adjusted endwise. Mounted on the rods between the shoe and the flange 38 are coil springs 43 yieldingly forcing the shoe against the face of the folder block 35. The outer ends of the rods are preferably connected by a cross bar 44 adapted to provide a handle for drawing the shoe out of contact with the folder block to permit the threading of the tape between the two, although normally the shoe is held against the block by the pressure of the springs 43.

The inner face of the shoe 40 which bears against the slotted face of the folder block 35 (Figure 11), is cut to provide a longitudinal channel throughout the greater portion of its length, having an inclined or tapering bottom so that it becomes shallower until at a'short distance from the opposite endof the shoe, the channel merges into a prO ecting tongue 46, extending throughout the remaining length of the shoe face. The maximum depth of the channel is approximately twice the maximum height of the tongue, the latter being substantially equal to the depth of the shallow recess in the face of the folder block 35. The bottom of the channel and the outer face of the tongue lie the folder block with the slotted portion on the right and the end of the slot facing in the direction from which the tape A is being advanced. Similarly, the tongue 46 fits into-the shallow recess in the face of the folder block near its opposite end and from which the tape leaves the same.

As already stated, the strip on leaving the mandrel is folded and creased into U-shape A, having the sectional contour shown in full lines'in Figure 12, and in this form is led directly to the entrance end of the slot formed between the folder block 35 and the shoe 40, although as shown in Figure 9, the entrance to the slot is of considerable width ow ng to the increased depth of the slot in the shoe. As the U-shaped strip enters the folder, its free edge portions are brought together by the flaring or tapered faces forming the entrance to the narrow slot 37 in the folder block, whereby the U-shape of Figure 12 is altered to that shown in Figure 13. On entering the slot between the block 35 and the shoe 40, the base or transverse portion of the U-folded strip is upright and outermost and therefore comes into contact with the inclined face of the channel 45 in the shoe. Moreover, due to the increased depth of the channel at its entrance end. a portion of the tape'on' either side of the upright edge is not immediately folded but retains its initial U-shape, as shown in Figure 13. But as the strip is advanced in contact with the tapering face of the channel in the shoe .40, those portions which lie outside of the narrow portion of the T-slot 37 are folded fiatwise against each other and compressed within the wider recess 37 a in the face of the folder block 37. This occurs at the point where the channel in the shoe disappears and the tongue 46 takes form, the strip then having taken'a T-form as shown in Figure 15, although the'tongue 46 hearing against the head or transverse portion of the T presses the two adjacent portions of the strip more forcibly against the shallow recess 37 in the folder block, produces an ironing effect, creasing the lines of fold and otherwise giving the strip a permanent set so that it will readily hold its T- shape A '(Figure 16) until it has been introduced into the edges of the board.

If desired. the shoe can be slightly modifled by omitting the tongue 46 and mounting.

at the exit end thereof a curved flat spring 47 extending beyond the shoe, and having its end pressing against the tape as it is advanced within the slot along the face of the folder block, as shown in Figure 18. In this construction the folder block 48 would be extended a greater distance beyond the shoe than in the folder previously described.

Referring now to Figures 1 and 2, the

strip now folded and creased to the form shown in Figure 16 and which may be indicated as A is advanced forwardly and in a slightly downwardly inclined direction over the table 4, Where it engages a guide or feed plate 49, previously mentioned. This feed plate is preferably of steel or brass and is of somewhat the same shape as the side dam 9, it being understood that there is one of these plates on each side of the .machine.

This plate is mounted just inside of the side dam-9, and preferably bolted directly thereto by a single bolt or pin passing through its central portion as at 50,so that it can be tilted. As a means of adjustment, another bolt 51 may be mounted near the rear edge of the feed plate 49 and engaging a slot 52 in the slde dam 9 so that by means of a wing nut 51 the angular adjustment of the guide plate may be easily made. The purpose of the angular ad ustment is to vary the angle of the lower edge of the feed plate to the horizontal, 1t being, noted that the tape passesfrom the last folder to the guide plate with a slight downward inclination. The-bottom edge of the feed plate 49 is raised above the surface of the bottom covering sheet 5 a distance equal to approximately one-half the thickness of the body of the plaster at the forward end of the plate. Along the bottom of the feed plate and in the outer face is a shallow rabbet 53 of a width and depth to take the upper half of the upright head portion of the T-shaped tape. And, finally, the forwardend ofthe feed plate is cut away to conform to the shapes of the upper roll 3, and to proyide a point at itslower edge projecting well 1n between the pressure rolls. The feed plate being positioned substantially in line with the edges of the sheets 5 and 8, it follows that as these sheets and the intermediate layer of wet plaster pass between the rolls the tape is simultaneously drawn or carried between the edges of the sheets with the stem portion of the'T-folded strip A embedded edgewise in the wet plaster midway of its thickness, and the upright or head portion of the strip disposed vertically between the edges of the covering sheets 5 and 8.

From the foregoing description, it will be seen that the apparatus, constructed and designed to'fold and crease the fabric tape, and then guide it into the board in the process of formation, may be applied to any continuous process machine for manufacturing what is termed trowelled edge plaster or wallboard. However, it is not intended that the invention shall be limited to the specific device herein disclosed, inasmuch as various refinements and modifications, which might occur to the skilled worker inthe art, may be adopted without departing from the spirit of the invention.

I claim as my invention:

, l. The combination with aplaster board machine, of apparatus for applying a reinforcing material along the edge of the board being made, comprising a series of folding base portion thereo devices through which a narrow strip of said material is successively fed, said devices act ing to first fold said strip into U-section and thence into T-section.

2. The combination with a plaster board machine, of apparatus for ap lying a remforcing material to the edge 0 the board being made, comprising a series of folding devices through which a narrow strip of sa d material is successively advanced, one of said devices acting to first fold said strip into U-form and the other to further fold the strip from said U-form to a T-form of dou ble thickness.

3. The combination with a plaster board machine, of apparatus for applying a reinforcing fabric along the edge of the board to be made, comprising a series of foldlng devices throu h which a narrow strip of said fabric is continuously advanced, said devices acting to first fold the strip lengthwise into U-shape and crease the same along its fold lines, and thence to fold the marginal portions of the U-stri together and upon the f to form a strip of T-section. a,

4. Thecombination with a plaster board machine, bf apparatus for applying a reinforcing material along the edge of the board as it is being made, comprising a series of folding devices through which a narrow strip of the material is continuously advanced, said devices acting to first fold the strip lengthwise into U-shape,'creasing thesame along its fold lines, and thence to fold the strip of U-section into a strip of T-section of double thickness of the material.

5. The combination with a plasterboard machine, of apparatus for folding a continuous strip of edge reinforcin material for the board being made on sai machine, comprising a fixed forming member mount ed in the path of said advancing strip, means for folding said strip in U-shape around said forming member, and a folding device adapted to fold the U-shaped strip into T-section. 6. The combination with a plasterboard machine, of apparatus for folding a continuous strip of reinforcing material for the edges of the board being made on said machine, comprising a mandrel mounted in the path of the advancing strip, members associated with said mandrel for folding said stri transversely about said mandrel into U-s ape and a folding device adapted to receive the U-shapedstrip and to further fold the same into, T-for'ni.

' 7, The-combination 'with a plasterboard machine, of apparatus forcontinuously foldin a strip of edge reinforcing material preparatory to ,being introduced into the edge of the board being made on saidma chine, comprising a fi'x'ed mandrel positioned inthe path of'the advancing material, and

having an edge portion of U-section, "'fold ing and creasing members bearing on said mandrel and adapted to fold said strip into U-shape, and a folding device beyond said first-mentioned folding device and adapted to fold the marginal portions of said U- shaped strip together and over upon the base portion thereof to form a strip of a T-section having portions of double thickness of the material.

8. The combination with a plasterboard machine, of apparatus for folding a continuous strip of edge reinforcing material for the board being made thereon, comprising a mandrel mounted in the path of said strip, pressure members acting to fold and crease the strip into U-shape in its passage over said mandrel, and a folding device having a -shaped bore adapted to receive the strip in U-form as it leaves said mandrel, and to fold the same into T-section in its passage therethrough.

9. The combination with a plasterboard machine, of apparatus for folding a narrow strip of reinforcing material as it is advanced toward the edge of the board to be reinforced thereby, comprising a mandrel mounted in the path of said strip and having a rectangular edge portion, pressure rollers bearing on the surfaces of said mandrel and conform ing to the sectional contour of the edge portion of said mandrel, and a folder block having a T-shaped slot adapted to receive the strip from said mandrel, and means associated with said folder block for gradually folding said strip into T-section during its passage along said slot.

10. The combination with a plasterboard machine, of apparatus for folding a strip of reinforcing material continuously advancing toward the edge of the board being made on said machine, comprising a mandrel mounted in the path of said strip, and having a forming edge of predetermined sectional contour, pressure rollers mounted adjacent said mandrel and adapted for rolling contact therewith, tension means acting on said rollers for normally holding the same in contact with said mandrel, and means for shifting said rollers bodily from said mandrelto permit the threading of the material between said rollers and said mandrel.

11. The combination with a plasterboard machine, of apparatus for folding a strip of edge reinforcing material as it advances toward the edge of the board being made thereon, comprising a fixed forming block mounted in the path of said strip and having an edge portion of square section, creasing members having yielding bearing contact with the forming block and acting to fold and crease the strip'into U-section in'its passage over said blocka folding member in advance of said forming block and consisting of a pair of blocks in yielding bearing contact, and having slots inthir bearing surfaces forming a bore of T-section, the same being tapered from end to end whereby said U-shapestrip is gradually distorted into T-shape during its passage therethrough.

121The combination with a plasterboard machine, of apparatus for folding a flat strip of reinforcing material being continuously advanced toward the edge of theboard being made thereon, comprising a forming member 13. The combination with a plasterboard machine, of apparatus for folding. and guiding a strip of edge reinforcing material to- Ward the edge of the board being made thereon, comprising a forming member in the path of said strip adapted toinitially fold and crease the strip into square U-section,, and a folding device beyond said forming member comprising-an elongated block havinga T-shaped recess in a longitudinal face of said block, a shoe yieldingly held in bearing contact with the recessed face of said' block, and having a channel in its contacting face decreasing in depth from end to end and registering with'said recess to form 'a bore. of T-section having a tapering head portion adapted to receive the advancing U-shaped strip at its larger end, and to gradually fold and crease the same into T-form during its passage through said bore.

14:. An apparatus for forming an edge reinforcing material for plasterboard and the like, comprising means for continuously advancing a fiat strip of fabric from a roll, forming members mounted in the path of said strip and adapted to fold the same lengthwise into U-form, with its edge and base portions folded at right angles to each other, and a folding device having a longitudinal slot of T-section through which said U-f0lded strip is advanced,said slot having a. portion tapering'from its entrance to its discharge end whereby the strip is folded into T-section with its edge portions folded together and over upon its base portion.

15. An apparatus for forming an edge reinforcirig material for plasterboard, comprisingmeans for continuously feeding a narrow strip of fabric from a suitable source of supply, forming members adapted to fold the advancing strip lengthwise into U-shape with its edge portions and base portion folded at right angles to each other, and a folding de vice adapted to receive the advancing folded strip and comprising a block having a longitudinal slot ofvT-section, the head portion of said T-slot being of substantial depth at its entrance end and tapering to a depth substantially equal to a double thickness oftho material of said strip, whereby the latter in U-shape is gradually distorted to a T-form,

with its edge portions folded together and over upon the base portion thereof. 1 a

16. An apparatus for folding a narrow strip of fabricinto edge reinforcing material of T-section for the edges of plasterboard and the like, comprising folding members adapted to fold the advancing strip into U-section, and means for further folding said strip into T-section comprising a folder block consisting of hinged-together sections havin their opposing faces slotted to form a longitudinal slot of -section opening edgewise along one face of said block, and a spring pressed shoe bearing against the slotted face of said block, and having a tapering channel in the bearing face thereof and registering with the 'slot in said block, and

a creasing member bearing in said slot be- 'yond said channel.

17. An apparatus for folding a ribbon like material "into T-form for reinforcing the edges of plasterboard and the like, including means for feeding the material in a predetermined path, folding members mounted in the path of the material, one of the same comprising a plate, a forming block mounted .on

said plate, and having faces arranged at right angles to each other, pressure rollers adapted to bear against said faces and mounted on lever arms journalled on said plate, tension means acting on said lever arms to hold said rollers in contact with said forming block, and means for manually actuating said.

lever arms to shift said rollers to permit the threading of said material between said rollers and said forming block.

18. The combination with a plasterboard machine, of means for folding a narrow strip of fabric into T-form and guiding the same into the edge of the board being made, comprising folded members adapted to fold the advancing strip into U form, a folding block having a bore of T-section through which the advancing U-shaped strip is fed, said bore being larger at its entrance end and tapering to a predetermined cross sectional dimension, whereby the U-folded strip is gradually folded into T-section, yieldable creasing members adapted to bear upon the advancmg T-shaped strip to crease the same along its fold lines and a strip guiding "member located adjacent the point where said T-strip'" enters the board.

19. The combination with a plasterboard machine having a pair of pressure rolls, of means for folding a narrow strip of material into T-form and guiding the same into the edge of the board being made, means for feeding the material toward said pressure rolls, folding members adapted to mitially fold the advancing strip into U-form, and thence int-o T-section of double thickness of g the material, and a guide plate mounted adjacent said pressure rolls and having a longitudinal groove substantially in line with the edge of the board being made on said machine, and adapted to guide the strip into 10 thleledge of said board adjacent said pressure 20. The combination with a plaster board machine, of means for folding a narrow strip of edge reinforcing material into T-form and guiding the same into the edge of the board being made. comprising means for supporting a.roll of the material rearwardly of the I pressure rolls of said machine, means for guiding the material toward. said pressure rolls, strip folding members in the path of said material and adapted to fold the same into U-section and thence into T-section, and a guide-plate mounted rearwardly of and adjacent to said pressure rolls, said plate having a groove along its lower edge conforming in section to that of the T-folded material, and means for adjusting the plate to Vary the angle of approach of said material to said pressure rolls. In testimony whereof I hereunto aifix my signature this 10th day of May, 1929.

- GUSTAVE A. NEW. 

